the mad trix will limit you totally. A 75 waist will make it almost impossible to do big mountain, and i'd guess it would be fairly unstable on landings aswell.
From what you've said, it sounds like you need something a bit fatter probably, something in the mid-80s would be better
Something like the Salomon Suspect, or the Volkl Ledge are good all-rounds skis, and won't limit you
But if you want to do mostly urban/ rails, then something like the Amplid C7 or Line Invader might be better.